Wedge lock stabilizer

Abstract

A drill string stabilizer in which the wall-contacting wear elements are secured in their accommodating slots by an undercut along each side and a tapered wedge-receiving notch along the underneath side for accepting one or more wedge pieces. In one embodiment, the tapered notch is along the side of an axially elongate slot and a plurality of wedges are located in securing position along one side. In another embodiment, there are tapered notches along the center between two separated sections of wear elements. In a third embodiment, the slot for the wear elements is not axially elongated but on a spiral angle. In a fourth embodiment, a pluraity of short wear elements are employed end-to-end, each with its own wedge piece and each also located on a thrust-bearing and locating pin.

What is claimed is: 
     
       1. A drill string stabilizer for accommodating and retaining a plurality of replaceable wear elements thereabout for contacting the surface of the borehole during drill string operation, said stabilizer having a body including a plurality of longitudinal slots of substantially uniform width, each of said slots being undercut to either side so that the width dimension at the surface of the stabilizer body is narrower than the undercut width,   at least one wear element fitting into each of said slots and conforming, on the underneath side thereof, at least on one side, with the undercut portion thereof,   the underneath side of said wear element also including a surface at a non-parallel angle with respect to the sides of said slot, said non-parallel angled surface including an undercut surface along at least a portion thereof, and   at least one tapered wedge bearing against said angled surface for holding said element in said slot and fitting at least in part within the undercut surface of said non-parallel angled surface and lying beneath the wear surface of said wear element.   
     
     
       2. A drill string in accordance with claim 1, wherein said angled surface on said wear element is a tapered slot having a configuration compatible with said tapered wedge. 
     
     
       3. A drill string stabilizer in accordance with claim 2, wherein there is a space between said element and the side of said slot above said wedge to permit operation of a tool for driving said wedge in tighter engagement and for loosening said wedge during removal. 
     
     
       4. A drill string stabilizer in accordance with claim 1, wherein said slot is elongated to permit insertion of said wedge and to permit operation of a tool for driving said wedge into tighter engagement and for loosening said wedge during removal. 
     
     
       5. A drill string stabilizer in accordance with claim 1, and including at least another tapered wedge, a first wedge being employed near one longitudinal end of said wear element and a second wedge being employed near the opposite longitudinal end of said wear element. 
     
     
       6. A drill string stabilizer in accordance with claim 1, wherein said wedge does not extend radially from said slot. 
     
     
       7. A drill string stabilizer for accommodating and retaining a plurality of replaceable wear elements thereabout for contacting the surface of the borehole during drill string operation, said stabilizer having a body including a plurality of longitudinal slots of substantially uniform width, each of said slots being undercut to either side so that the width dimension at the surface of the stabilizer body is narrower than the undercut width,   at least one wear element fitting into each of said slots and conforming, on the underneath side thereof, at least on one side, with the undercut portion thereof, the underneath side of said wear element also including a surface at a non-parallel angle with respect to the sides of said slot, and     at least one tapered wedge bearing against said angled surface for holding said element in said slot said wear element including first and second longitudinal sections,   said first section having a side conforming with a first undercut side of said slot and said second section having a side conforming with the second undercut side of said slot,   said angled surface being at least one of the underneath facing surfaces of said first and second sections,   said tapered wedge bearing outwardly against both said first and second sections.   
     
     
       8. A drill string stabilizer in accordance with claim 1, and including thrust means between said wear element and said stabilizer body. 
     
     
       9. A drill string stabilizer in accordance with claim 8, wherein said thrust means includes a radial projection underneath said wear element and an aligned receiving hole within the confines of said slot for accommodating said projection. 
     
     
       10. A drill string stabilizer in accordance with claim 1, and including at least a second wear element fitting into each of said slots and conforming on the underneath side thereof, at least on one side, with the undercut portion thereof, said second wear element longitudinally abutting said first-named wear element, the underneath side of said second wear element also including a surface at an angle with the side of said slot having an undercut surface along at least a portion thereof, and   at least a second tapered wedge bearing against said angled surface of said second wear element for holding said element in said slot and fitting at least in part within the undercut surface of said angled surface and lying beneath the wear surface of said second wear element.   
     
     
       11. A drill string stabilizer in accordance with claim 10, and including at least a third tapered wedge bearing against said angled surface of said first-named wear element longitudinally displaced from said first wedge for independent holding of separate portions of said first-named wear element within the slot and fitting at least in part within the undercut surface of said angled surface and lying beneath the wear surface of said first named wear element, and   at least a fourth tapered wedge bearing against said angled surface of said second wear element longitudinally displaced from said second wedge for independent holding of separate portions of said second wear element within the slot and fitting at least in part within the undercut surface of said angled surface and lying beneath the wear surface of said second wear element.   
     
     
       12. A drill string stabilizer in accordance with claim 1, wherein said slots are not parallel with the longitudinal axis of said stabilizer body. 
     
     
       13. A drill string stabilizer in accordance with claim 1, wherein said non-parallel angled surface is notched for receiving said tapered wedge. 
     
     
       14. A drill string stabilizer in accordance with claim 13, wherein said tapered wedge includes a surface conforming with the undercut portion of said slot opposite that to which the underneath side of said wear element conforms.